1. The Field of the Invention
The present invention relates to laser apparatus used for purposes of surgery and, more particularly, to a disposable laser endocoagulator apparatus for ophthalmic surgery.
2. The Prior Art
The advent of the laser has opened new frontiers to many areas of science and has revolutionized many procedures. One of the most important of these new frontiers has been the application of laser technology to various procedures in the field of medicine. Because lasers can be focused onto very small areas, it is possible to be very precise and to treat specific pathologies without affecting surrounding tissue.
The first significant medical use of a laser occurred in 1965 when doctors utilized a laser to repair a detached retina. The surgeons were able to focus the laser into the interior portion of the eyeball and "weld" the detached retina back into place. At the point where the laser beam struck the retina, the light energy was converted into heat energy which produced a coagulum. During the next few weeks, this coagulum was converted to scar tissue which anchored the retina in place. Since that time, the procedure has been much improved and the utilization of lasers has become a generally accepted method of repair in this type of abnormality. Surgical laser apparatus has also been used to repair retinal tears and abnormal blood vessels within the eye.
Notwithstanding the substantial advances in ophthalmic surgery which have come about as a result of the improvements in laser technology, the current state of the art leaves much to be desired. For example, in the past it has been common practice to use xenon lasers for purposes of ophthalmic surgery. The laser beam from a xenon laser has a tendency to scatter to a certain degree, thus losing some of its intensity and precision. Because of this tendency, the tip of the optical fiber through which the laser beam passes must almost be in contact with the eye tissue which is being treated. Since ophthalmic surgery is typically conducted in the dark so that only the area of the eye on which the surgery is occurring is illuminated, this increases the possibility of causing additional damage to the eye because the surgeon, in attempting to place the tip of the optical fiber so that it is almost in contact with the eye tissue, may accidentally touch the tissue causing a further tear or causing physical damage to surrounding tissue.
The laser endocoagulators used for ophthalmic surgery have typically been rather complicated in their structure. For example, typically the handtool of a laser endocoagulator is quite expensive in its construction because it is made entirely from stainless steel. Thus, the practice in the art has been to resterilize the entire endocoagulator so that it can be reused time after time. However, not only are such resterilization techniques time consuming and expensive in terms of additional labor and handling, but it also renders it more difficult to maintain the delicate optical fiber of the endocoagulator in top condition. For example, it is important that the end of the optical fiber be polished and free from debris so that the laser beam will be transmitted without interference. Any irregularity in the tip of the optical fiber may cause a portion of the light to be absorbed, thus decreasing the amount of the light transmitted causing the tip of the fiber to become overheated, as well as degrading the quality of the laser beam omitted from the tip of the fiber.
Additionally, the connectors utilized to attach the optical fiber to the laser source have generally consisted of a number of very carefully machined metal parts adapted to fit together with great precision so as to accurately align the optical fiber with the laser beam. If the laser beam is not properly aligned with the end of the optical fiber, much of its power can be lost. Additionally, the misdirected beam can vaporize portions of the connector, thus destroying it or creating debris which can obscure the end of the fiber.
Some of the connectors used in the prior art have incorporated a series of lenses to focus the laser beam onto the end of the optical fiber. Many prior art type connectors also incorporate a convex, gold collar disposed about the end of the optical fiber so as to provide an inert reflective surface for the laser beam in the event that it is not precisely aligned with the end of the optical fiber.
While these prior art connectors have proven effective, they are disadvantageous for several reasons. First, such connectors are very expensive to manufacture because of the number of parts that must be carefully machined so as to fit together within extremely close tolerances. While this disadvantage is partially offset by the fact that the connectors are reusable, this creates a second problem. The optical fiber held between the probe and the connector is typically in need of repair or replacement after only a few surgical operations. Because of the need for extremely precise positioning of the optical fiber within the endocoagulator and its connector, it has heretofore been necessary to send the entire assembly back to the factory for repair or replacement. Since the time required for these repairs is generally several weeks, it has proven necessary for hospitals performing large numbers of ophthalmic operations to have many endocoagulator assemblies in their inventory. This requires a large capital outlay and significant inventory cost.
Another problem associated with prior art laser endocoagulators is the need to insure that they are absolutely sterile before reuse. Inasmuch as the tip of the probe is inserted within the eye, extreme care must be taken to insure that the probe is completely sterile to prevent the introduction of bacteria.
Thus, what is needed in the art is a laser endocoagulator apparatus which is very simple in its construction and which is economical to manufacture so that it can be easily disposed of after a single use, and which effectively overcomes the disadvantages of the prior art type endocoagulators mentioned above.